The candidate is currently a Pappalardo Postdoctoral Fellow in the laboratory of Professor Alexander van Oudenaarden in the Department of Physics at the Massachusetts Institute of Technology. The candidate was awarded a PhD in Physics from the University of California, Berkeley for research in the field of single- molecule biophysics. During the Postdoctoral Fellowship, the candidate is transitioning to the field of systems biology. The candidate will apply the quantitative techniques from previous research to the study of evolutionary game dynamics in microbial systems. The NIH Pathway to Independence Award would provide necessary support to the candidate during this transition period. The award would allow the candidate to continue to acquire new skills in the techniques of in vivo experimental biology specifically the use of bacterial and yeast cell culture, flow cytometry, and molecular genetics and analysis. The candidate has developed and engaged in a research proposal to study the evolution of cooperation in S. cerevisaie sucrose metabolism. During the Postdoctoral phase of the award, the candidate will 1) Develop theoretical and experimental approaches to understand the nature of sucrose metabolism 2) Explore cooperative and competitive interactions in sucrose metabolism 3) Study the effect of spatial structure on the evolution of cooperative interactions. These aims will be accomplished by genetically engineering "cooperator" and "cheater" strains of S. cerevisiae and growing these strains in direct competition in liquid culture. The results of these competition experiments will be monitored through a combination of fluorescence microscopy and flow cytometry. During the independent phase of the award, the candidate will extend the research to the cooperative and competitive interactions that govern the production of iron-scavenging siderophores by the bacteria E. coli. The candidate ultimately desires to pursue an academic career in research and teaching. Relevance: The evolution of cooperation is a classic problem in evolutionary biology with important implications for the study of cancer and infectious diseases. Multi-cellular life is a prime example of cellular cooperation; cancer results when one cell ceases this cooperation and begins to divide uncontrollably. Similarly, the virulence of infectious diseases can depend upon the nature of cooperative or competitive interactions between infecting microbes and the host. [unreadable] [unreadable] [unreadable]